1. Technical Field
The embodiments herein generally relate to organic light emitting diode processing and characterization, and more specifically, to a high throughput combinatorial screening through novel substrates and techniques.
2. Description of the Related Art
The ability to process uniformly across a monolithic substrate and/or across a series of monolithic substrates is advantageous for manufacturing efficiency and cost effectiveness, as well as repeatability and control. However, uniform processing across an entire substrate can be disadvantageous when optimizing, qualifying, or investigating new materials, new processes, and/or new process sequence integration schemes, since the entire substrate is nominally made the same using the same materials, processes, and process sequence integration scheme. In conventional processing systems, each processed substrate generally represents, in essence, only one possible variation per substrate. Thus, the full substrate uniform processing under conventional processing techniques results in fewer data points per substrate, longer times to accumulate a wide variety of data, and higher costs associated with obtaining such data.
For example, in current systems, indium tin oxide (ITO) is used as an anode material in organic light emitting diode (OLED) devices. In general, OLED devices use an emissive electroluminescent layer made of an organic semiconductor to emit light in response to an electric current. For example, light is emitted in the emissive electroluminescent layer as an applied voltage causes a current of electrons to flow from the anode to a cathode. In OLED applications, the anode material is typically transparent and thereby allows the light emitted from the emissive electroluminescent layer to pass therethrough. Since ITO is transparent, this makes ITO a suitable material in limited situations. ITO, however, has several drawbacks, including a high manufacturing cost that, in turn, affects the price of devices based on OLED technology and thereby affects the ability of OLED-based devices to fully realize their potential in the marketplace. The high manufacturing cost of ITO is attributed to, for example, the cost of indium, special equipment capable of accommodating the fragility of ITO, and the cost of deposition equipment, wherein ITO requires deposition in a vacuum.
What is needed is an alternative to ITO that is also a transparent conductor. Significant development gain can be obtained, for example, by identifying transparent conductors that can be deposited efficiently and cost effectively. Conventional research and development, however, is slow and costly. For example, to know the result of each condition (e.g., as part of a design of experiments matrix), one wafer or coupon with many follow-up steps is required, which under current technology is very complicated as well as cost inefficient. In particular, OLED companies conduct research and development (R&D) on full wafer processing through the use of split lots, as the deposition systems are designed to support this processing scheme. This approach has resulted in high R&D costs and the inability to conduct extensive experimentation in a timely and cost effective manner. Therefore, what is needed is an efficient experimental methodology to identify new transparent conductors.